China’s Liaoning aircraft carrier and six accompanying navy warships are conducting military training with fighter jets and helicopters in the Western Pacific Ocean, the Japanese Defense Ministry announced Wednesday.

The ongoing drills Tuesday in waters that are closely monitored by Japan were likely intended to check military activities in the same area by the U.S., Japan and others, especially as the allies become increasingly vocal over the fate of self-ruled Taiwan, which China claims as a renegade province.

The ministry said that the exercises had taken place about 160 kilometers southwest of Okidaito Island. It said earlier that the flotilla of Chinese Navy ships on Monday had passed through the Miyako Strait — a key gateway into the Western Pacific Ocean near Okinawa Prefecture.